A single-control valve is connected to both the hotand cold-water feed lines and typically has an arm projecting from the valve housing and that is moved in one manner, normally angularly, to control the temperature of the water coming out of a faucet or other fitting connected to the valve and in another manner, normally up and down, to determine the volume of flow. Such a valve can also be used as a flow splitter or other type of mixing valve, in which case the connections are switched around with what would normally be connected to the two incoming lines connected to the two places the flow is to be split between and what is normally connected to the outgoing line connected to the source whose flow is to be split.
German patent document 1,550,060 filed Mar. 24, 1966 by R. G. Parkison describes such an arrangement having a stationary valve plate formed with a large-diameter outgoing-water port and, spaced therefrom, separate smaller hot- and cold-water incoming ports. A movable plate sitting atop this stationary plate has a single large chamber or port and this movable plate can be twisted angularly so that this chamber can overlap all three of the ports for mixing, can interconnect one of the outgoing ports with the incoming port for pure hot- or cold-water flow, or can overlap only the outgoing port for no flow. Similarly radial shifting of the movable valve plate varies the flow cross sections of the ports and thereby determines the volume/time rate of flow.
In this arrangement the movable valve plate is nonrotatable in an upper valve member that can rotate about the axis. A control lever is pivoted in the upper member and passes out through a cap secured to it, so that as this lever is raised and lowered to shift the movable plate radially it tips the entire cap, which must be made a fairly loose fit. When the lever is swung to the side the cap must similarly follow its movement. Thus the arrangement is fairly bulky due mainly to the size of the cap.
In German patent document 3,137,774 filed Sept. 23 1981 by W. P. Herring a similar such arrangement is shown, but where instead of a cap the lever projects out of a large hole in the top of the system. Otherwise this arrangement functions identically to that of Parkison. This hole is a trap for dirt and is generally unsightly.
Another arrangement described in German Pat. No. 1,759,520 filed May 10, 1968 by F. Bayer has a vertically displaceable valve element controlled by a lever projecting through a window in the side of the valve housing. This arrangement is quite tall and is particularly difficult to install, remove, and service.
Further similar such devices can be seen in U.S. Pat. Nos. 2,503,881, 2,989,985, 3,035,612, and 3,168,112 as well as in the other references cited in the above-discussed patent documents.